1. Field
The following description relates to a technology of adaptively setting a transmission power of a femtocell in a mobile communication environment. More particularly, the following description relates to an apparatus and method for setting a transmission power of a femtocell that may maintain a Quality of Service (QoS) of a communication terminal as stably as possible when a transmission power is limited, and that may reduce energy consumption of a cell caused by setting a suitable transmission power.
2. Description of Related Art
A macrocell may provide a service over a relatively wide range. However, in the macrocell, it is difficult for an electromagnetic wave to reach an indoor space, such as a building or a house. As a result, there is a shadow area in which data is not effectively transmitted.
A femtocell refers to a compact base station that may be installed by a personal provider and a communication provider and that may support mobile communication service in a radius that is typically smaller than the coverage area of a macrocell. The femtocell may be installed in the shadow area of the macrocell, thereby supporting a smooth mobile communication service.
Because the femtocell may be connected directly to a core network using an ultra high-speed Internet connectable to an indoor space, the femtocell has an advantage of low installation and maintenance costs.
Additionally, the femtocell may use a significantly smaller amount of energy in order to maintain the same level of transmission power, compared with a macrocell.
Furthermore, prospects of femtocells are good, based on a rapid increase in a proportion of high-capacity data traffic of a terminal using a mobile terminal service, and based on supplies of channel resources required to provide services becoming more scarce.
In a current macrocell, it is difficult to use a high frequency for a stable bandwidth allocation. However, in a femtocell, it is possible to support a band of a high frequency while using low transmission power. Additionally, the femtocell may be expected to sufficiently and stably support channel resources, due to a relatively small number of terminals supported by each femtocell, for example, about five terminals.
The femtocell may be a critical equipment for a next-generation mobile communication network, and a usefulness of the femtocell may be expected to be sharply increased.
As a use of a femtocell is expected to rapidly increase, an interference between a femtocell and a macrocell, and interferences between different femtocells are emerging as important issues. Accordingly, to prevent the interferences, a transmission power of the femtocell may be set low. However, a reduction in power may cause problems such as a transmission radius to be reduced and a failure to satisfy a Quality of Service (QoS) required by a communication terminal.